We have recently run into some questionable behavior on Mathoverflow: occasional users asked a question, it received a valid answer, and then the question was deleted immediately before the answer had time to gather upvotes. In one case we guess that it is because the poster found the question embarrassingly simple in retrospect, in the other there was clearly some malicious intent (plagiarism).

Anyways, it looks like this is a bad habit that should be forbidden, because those answers require time to write, and it is value that goes lost to all other users.

The current policy is that the asker can delete their own question (and its associated answers) as long as there is at most one answer with no upvotes.

One possible fix would be disallowing deletion of answered questions altogether, irrespective of their score. Another fix would be allowing deletion only after a certain time since the last posted answer, like a couple of days. In this way, good answers have some time to gather upvotes.


  • changing the condition so that the question can be deleted only if it has an answer with score < 0 is not a fix, because the asker can downvote the answer and then delete. Changing it to score < 3, for instance, would encourage sock-puppeting, and reduce a lot the cases when this rule is applicable.

  • the asker has no legal right to have their own question deleted, because they licensed it to SE under a CC license and they cannot take away this license once it has been granted. I see no moral obligations either.

  • It is particularly hard to catch this behavior after the question has been deleted, because deleted questions have very low visibility currently (they only appear as a link in the moderator queue, I believe?).

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    Have you already seen this? Jul 8, 2018 at 13:27
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    @AnneDaunted No, I searched for something similar but I didn't manage to find it. Thanks for bringing it up. I still regard those answers as unsatisfactory, though, and I believe that the plagiarism issue (which may be Mathoverflow-specific) takes this problem to a whole new level. Jul 8, 2018 at 13:31
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    Yeah.. this happens often, expecially at the weekend when homework is due in by Monday morning:( Jul 8, 2018 at 15:10
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    And the deleted question is practically invisible, so these things are super-hard to audit. Jul 8, 2018 at 15:18
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    This issue has also previously been raised on math.meta. Jul 9, 2018 at 8:32

1 Answer 1


This feature request from 2012 asked for a 24-hour delay before questions could be deleted, and was quasi-declined at the time because this was considered an edge case and people could just flag if it happens. Years later we should revisit the problem for the following reasons:

  • As you note, this has been an ongoing problem on some sites.

  • And maybe it's a problem on more sites, because how would we know? Moderators have a list of recent self-deletions but the community does not; there's basically no way to audit these deletions.

  • Except people could flag -- if they saw the question and have the URL in a browser tab or inbox, or if they answered it. That, too, is a pretty small group of people, and they have to notice that the post was deleted. If you answer a question, move on, later wonder why you've gotten no comments or votes, and go looking for it and find it gone, are you going to find your way back to it? Is that a good user experience?

  • We are, especially recently, trying to focus more on new users and being welcoming. When a new user, one who doesn't already know about "show recent deleted posts" and flagging and deletion rules, let alone meta, contributes good work that apparently vanishes without a trace, how do you think that user is going to react? Is that welcoming or off-putting? Should we really expect that person to keep contributing?

We already have some time limits built into SE. One is that you can't bounty or accept a self-answer on a question for at least two days. That limit was set to allow time for the community to act -- to improve or close a question before a bounty pins it open, or to provide competing answers before the asker marks the question (self-)answered, perhaps deterring other answers. Two days seems a reasonable limit here too -- you can't delete your question within the first 48 hours after receiving an answer. (A second answer prevents self-deletion regardless of score, so we only have to count from the first answer, not the most recent answer.)

If somebody "needs" to delete a question more quickly and argues that an existing answer is poor and shouldn't block deletion, there's a simple solution: seek deletion of the answer. But if the answer isn't worthy of deletion directly, then it shouldn't be worthy of deletion by the person who asked the question.

Or, failing that, explain the problem to a moderator. If your question was a "duh" typo and removing the embarrassing question with your name on it is being blocked by a FGITW one-line correction, you can probably persuade a moderator that nothing of value will be lost by deleting the question. But an asker who might have ulterior motives, like hiding his cheating on homework, wouldn't be able to waste the time of other community members who invested effort providing help.

  • Re "Moderators have a list of recent self-deletions but the community does not": does this mean that self-deletions don't show in the moderation tools where 20k-rep users can see a list of recently deleted posts? Jul 9, 2018 at 8:35
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    @PeterTaylor it appears not. For example, this question (10k Worldbuilding) and this answer (10k Mi Yodeya) do not show in "recently deleted". I think that list only shows community and Community deletions; red-flag deletions don't show up there either. Jul 9, 2018 at 15:12

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